Chapter 2

The Brain

The Brain

Lesion tissue

destruction a brain lesion

is a naturally or experimentally caused destruction of brain tissue

Electroencephalogram (EEG)

an amplified recording of the waves of electrical activity that sweep across the brain’s surface

these waves are measured by electrodes placed on the scalp

The Brain CT (computed tomography) Scan

a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body; also called CAT scan

PET (positron emission tomography) Scan a visual display of brain activity that detects where a

radioactive form of glucose goes while the brain performs a given task

MRI (magnetic resonance imaging) a technique that uses magnetic fields and radio waves to

produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain

PET Scan

MRI Scan

The Brain

Brainstem the oldest part and central core of the

brain, beginning where the spinal cord swells as it enters the skull

responsible for automatic survival functions Medulla [muh-DUL-uh]

base of the brainstem controls heartbeat and breathing

The Brain

The Brain

Reticular Formation a nerve network in the brainstem that plays

an important role in controlling arousal Thalamus [THAL-uh-muss]

the brain’s sensory switchboard, located on top of the brainstem

it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

The Brain

Cerebellum [sehr-uh-BELL-um] the “little brain”

attached to the rear of the brainstem

it helps coordinate voluntary movement and balance

The Brain Limbic System

a doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres

associated with emotions such as fear and aggression and drives such as those for food and sex

includes the hippocampus, amygdala, and hypothalamus.

Amygdala [ah-MIG-dah-la] two almond-shaped neural clusters that are

components of the limbic system and are linked to emotion

The Brain Hypothalamus

neural structure lying below (hypo) the thalamus; directs several maintenance activities eating drinking body temperature

helps govern the endocrine system via the pituitary gland

is linked to emotion

The Limbic System

The Limbic System

Electrode implanted in reward center

The Cerebral Cortex

Cerebral Cortex the intricate fabric of

interconnected neural cells that covers the cerebral hemispheres

the body’s ultimate control and information processing center

Glial Cells cells in the nervous system that

support, nourish, and protect neurons

The Cerebral Cortex

Frontal Lobes involved in speaking and muscle movements

and in making plans and judgments Parietal Lobes

include the sensory cortex Occipital Lobes

include the visual areas, which receive visual information from the opposite visual field

Temporal Lobes include the auditory areas

The Cerebral Cortex

The Cerebral Cortex

Motor Cortex area at the rear of the frontal lobes that

controls voluntary movements Sensory Cortex

area at the front of the parietal lobes that registers and processes body sensations

The Cerebral Cortex

The Cerebral Cortex

Functional MRI scan shows the visual cortex activated as the subject looks at faces

Visual and Auditory Cortex

Association Areas More intellegent animals have increased

“uncommitted” or association areas of the cortex

The Cerebral Cortex Aphasia

impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding)

Broca’s Area an area of the left frontal lobe that directs

the muscle movements involved in speech Wernicke’s Area

an area of the left temporal lobe involved in language comprehension and expression

Specialization and Integration

Specialization and Integration

Brain activity when hearing, seeing, and speaking words